Insulating into floor joists on 2nd floor flat.

[Blokefella]

Quick question you lovely people.

Will likely insulate my new flat between floor joists with acoustic wool slabs, to soundproof from the downstairs flat.

I dont know the depth yet but is it advisable to leave an air void between the insualtion and the underside of the floor panels?

I ask as I could also fit some kingspan on top of mineral rockwall,as I can get a load of offcuts from work for free.

Would it harm if I packed the joists completly or is it a no no?

Many thanks.

 

[Blokefella]

any ideas?

 

[geraldthehamster]

There's no need for an air gap but make sure you don't embed any wiring in the insulation. Kingspan is useless for sound insulation.

Cheers
Richard